Solar Control Coating With Discontinuous Metal Layer

ABSTRACT

An architectural transparency includes a substrate; a first dielectric layer over at least a portion of the substrate, a first metallic layer over the first dielectric layer, a first primer layer over the first metallic layer, a second dielectric layer over the first primer layer, a second metallic layer over the second dielectric layer, a second primer layer over the second metallic layer, a third dielectric layer over the second primer layer, a third metallic layer over the third dielectric layer, a third primer layer over the third dielectric layer, and a fourth dielectric layer over the third primer layer. At least one of the metallic layers is a subcritical metallic layer.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/842,118 filed Dec. 14, 2017, which is a continuation of U.S. patentapplication Ser. No. 13/072,866 filed Mar. 28, 2011, now U.S. Pat. No.9,932,267 issued Apr. 3, 2018, which claims priority to U.S. ProvisionalApplication No. 61/318,471, filed Mar. 29, 2010, the disclosures ofwhich are hereby incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates generally to solar control coatings and, in oneparticular embodiment, to a solar control coating having increasedabsorbance and asymmetrical reflectance.

Technical Considerations

Solar control coatings are known in the fields of architectural andautomotive transparencies. These solar control coatings block or filterselected ranges of electromagnetic radiation, such as in the range ofsolar infrared or solar ultraviolet radiation, to reduce the amount ofsolar energy entering the vehicle or building. This reduction of solarenergy transmittance helps reduce the load on the cooling units of thevehicle or building. In automotive applications, the transparency (suchas a windshield) is typically required to have a relatively high visiblelight transmittance, such as greater than 70 percent, to allowpassengers to see out of the vehicle. For architectural applications,the visible light transmittance can be lower. In some architecturalapplications, it may be desirable to have a reflective outer surface soas to decrease visibility into the building to retain as much privacy aspossible, while still allowing visible light to enter the building andalso allowing the workers inside the building to see out. Also, thesetransparencies are typically tempered or heat treated for increasedsafety.

In one known architectural transparency, a heat strengthened glasssubstrate is coated with a solar control coating having an absorbermaterial, such as a nickel-chromium alloy material (e.g., Inconel®), toabsorb visible light to darken the window. This transparency alsoincludes a relatively thick, continuous, infrared reflective metal layerto reflect solar energy, such as solar infrared energy. However, aproblem with this known transparency is that the glass substrate must becut to a desired shape and tempered before the coating is applied. Ifthe coating is applied before the glass substrate is tempered, theresultant coating becomes hazy during the high temperature processingsrequired for the tempering process. This haze is aestheticallyundesirable.

It would be desirable to be able to apply a solar control coating ontonon-tempered glass sheets and ship the glass sheets to a manufacturerwho could then cut the sheets to a desired size for a particular job andthen temper or heat treat the cut pieces without adversely impactingupon the aesthetic or solar control properties of the resultanttransparency.

SUMMARY OF THE INVENTION

In one broad aspect of the invention, the coating of the inventionincludes one or more continuous, infrared reflective metal layers incombination with a subcritical (i.e., discontinuous) metal layer. Thediscontinuous metal layer increases the visible light absorption of thecoating and, in combination with dielectric layers of appropriatethickness, can also provide the coated article with asymmetricalreflectance.

A coating of the invention comprises a plurality of metallic layersalternating with a plurality of dielectric layers, with at least one ofthe metallic layers comprising a subcritical metallic layer havingdiscontinuous metal regions.

A coated article comprises a substrate and a coating stack over at leasta portion of the substrate. The coating stack comprises a plurality ofmetallic layers and a plurality of dielectric layers, wherein at leastone of the metallic layers comprises a subcritical metallic layer havingdiscontinuous metallic regions.

Another coated article comprises a glass substrate and a coating formedover at least a portion of the glass substrate. The coating comprises afirst dielectric layer formed over at least a portion of the glasssubstrate; a continuous metallic layer formed over at least a portion ofthe first dielectric layer; a second dielectric layer formed over atleast a portion of the first metallic layer; a subcritical metalliclayer formed over at least a portion of the second dielectric layer suchthat the subcritical metallic layer forms discontinuous metallicregions; a third dielectric layer formed over at least a portion of thesubcritical metallic layer; a third continuous metal layer formed overat least portion of the third dielectric layer; a third dielectric layerformed over at least a portion of the third metal layer; and aprotective layer formed over at least a portion of the third metalliclayer.

A further coated article comprises a substrate and a coating comprisinga first dielectric layer formed over at least a portion of thesubstrate; a first metallic layer formed over at least a portion of thefirst dielectric layer; a second dielectric layer formed over at least aportion of the first metallic layer; a second metallic layer formed overat least a portion of the second dielectric layer; and a thirddielectric layer formed over at least a portion of the second metalliclayer. At least one of the metallic layers is a subcritical metalliclayer having discontinuous metallic regions.

An additional coated article comprises a substrate and a coating stackover at least a portion of the substrate. The coating stack comprises afirst dielectric layer; at least one discontinuous metallic layer overthe first dielectric layer; and a second dielectric layer over thediscontinuous metallic layer. A further coated article comprises asubstrate and a coating formed over at least a portion of the substrate.The coating comprises a first dielectric layer formed over at least aportion of the substrate and comprising a zinc oxide layer over a zincstannate layer; a first, continuous metallic silver layer comprisingsilver over the first dielectric layer; a first primer layer over thefirst continuous metallic silver layer, the first primer comprisingtitanium; a second dielectric layer over the first primer layercomprising a zinc stannate layer over a zinc oxide layer; a second,discontinuous metallic silver layer over the second dielectric layer; asecond primer over the second discontinuous metallic silver layer andcomprising a nickel-chromium alloy; a third dielectric layer over thesecond primer layer and comprising a zinc oxide layer, a zinc stannatelayer, and another zinc oxide layer; a third continuous metallic silverlayer over the third dielectric layer; a third primer layer comprisingtitanium over the third continuous metallic silver layer; a fourthdielectric layer comprising a zinc stannate layer over a zinc oxidelayer over the third primer layer; and a protective coating comprisingtitania over the fourth dielectric coating.

An architectural transparency of the invention comprises a substratehaving a first dielectric layer formed over at least a portion of thesubstrate. A continuous metallic layer is formed over at least a portionof the first dielectric layer. A second dielectric layer is formed overat least a portion of the first metallic layer. A subcritical metalliclayer is formed over at least a portion of the second dielectric layersuch that the subcritical metallic layer forms discontinuous metallicregions. A third dielectric layer is formed over at least a portion ofthe subcritical metallic layer. The metals of the continuous metalliclayer and the subcritical metallic layer can be the same or differentmetals.

Another architectural transparency of the invention comprises a glasssubstrate with a first dielectric layer formed over at least a portionof the glass substrate. A continuous first metallic layer is formed overat least a portion of the first dielectric layer. A second dielectriclayer is formed over at least a portion of the first metallic layer. Asecond metal layer (subcritical metallic layer) is formed over at leasta portion of the second dielectric layer such that the subcriticalmetallic layer forms discontinuous metallic regions. A third dielectriclayer is formed over at least a portion of the subcritical metalliclayer. A continuous third metal layer is formed over at least a portionof the third dielectric layer. A protective layer is formed over atleast a portion of the third metallic layer. The metals of thecontinuous metallic layers and the subcritical metallic layer can be thesame or different metals. A fourth dielectric layer is formed over atleast a portion of the third metallic layer under the protective layer.

A further architectural transparency comprises a substrate with a firstdielectric layer formed over at least a portion of the substrate. Acontinuous first metal layer is formed over at least a portion of thefirst dielectric layer. An absorbing layer is formed over at least aportion of the first metal layer. The absorbing layer comprises a firstsilicon nitride film, a metal layer formed over at least a portion ofthe first silicon nitride film, and a second silicon nitride film formedover the metal layer.

Another architectural transparency comprises a glass substrate with afirst dielectric layer formed over at least a portion of the glasssubstrate. A continuous first metal layer is formed over at least aportion of the first dielectric layer. A first primer layer is formedover at least a portion of the first metal layer. The first primer layercomprises a multi-film layer. A second dielectric layer is formed overthe first primer layer. A second continuous metal layer is formed overthe second dielectric layer. A second primer layer is formed over thesecond metal layer. The second primer layer comprises a multi-filmlayer. The first and second primer layers can comprise a nickel-chromiumalloy layer (such as Inconel) and a metal layer, such as titanium.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the following drawingfigures wherein like reference numbers identify like parts throughout.

FIG. 1 is a side view (not to scale) of an insulating glass unit (IGU)having a coating of the invention;

FIG. 2 is a side view (not to scale) of a coating incorporating featuresof the invention;

FIG. 3 is a side, sectional view (not to scale) of a subcritical metallayer with a primer layer;

FIG. 4 is a side view (not to scale) of another coating incorporatingfeatures of the invention;

FIG. 5 is a side view (not to scale) of a further coating incorporatingfeatures of the invention;

FIG. 6 is a side view (not to scale) of a still further coatingincorporating features of the invention; and

FIG. 7 is a side, sectional view (not to scale) of a further coating ofthe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein, spatial or directional terms, such as “left”, “right”,“inner”, “outer”, “above”, “below”, and the like, relate to theinvention as it is shown in the drawing figures. However, it is to beunderstood that the invention can assume various alternativeorientations and, accordingly, such terms are not to be considered aslimiting. Further, as used herein, all numbers expressing dimensions,physical characteristics, processing parameters, quantities ofingredients, reaction conditions, and the like, used in thespecification and claims are to be understood as being modified in allinstances by the term “about”. Accordingly, unless indicated to thecontrary, the numerical values set forth in the following specificationand claims may vary depending upon the desired properties sought to beobtained by the present invention. At the very least, and not as anattempt to limit the application of the doctrine of equivalents to thescope of the claims, each numerical value should at least be construedin light of the number of reported significant digits and by applyingordinary rounding techniques. Moreover, all ranges disclosed herein areto be understood to encompass the beginning and ending range values andany and all subranges subsumed therein. For example, a stated range of“1 to 10” should be considered to include any and all subranges between(and inclusive of) the minimum value of 1 and the maximum value of 10;that is, all subranges beginning with a minimum value of 1 or more andending with a maximum value of 10 or less, e.g., 1 to 3.3, 4.7 to 7.5,5.5 to 10, and the like. Further, as used herein, the terms “formedover”, “deposited over”, or “provided over” mean formed, deposited, orprovided on but not necessarily in contact with the surface. Forexample, a coating layer “formed over” a substrate does not preclude thepresence of one or more other coating layers or films of the same ordifferent composition located between the formed coating layer and thesubstrate. As used herein, the terms “polymer” or “polymeric” includeoligomers, homopolymers, copolymers, and terpolymers, e.g., polymersformed from two or more types of monomers or polymers. The terms“visible region” or “visible light” refer to electromagnetic radiationhaving a wavelength in the range of 380 nm to 800 nm. The terms“infrared region” or “infrared radiation” refer to electromagneticradiation having a wavelength in the range of greater than 800 nm to100,000 nm. The terms “ultraviolet region” or “ultraviolet radiation”mean electromagnetic energy having a wavelength in the range of 300 nmto less than 380 nm. Additionally, all documents, such as, but notlimited to, issued patents and patent applications, referred to hereinare to be considered to be “incorporated by reference” in theirentirety. As used herein, the term “film” refers to a coating region ofa desired or selected coating composition. A “layer” can comprise one ormore “films”, and a “coating” or “coating stack” can comprise one ormore “layers”. The term “asymmetrical reflectivity” means that thevisible light reflectance of the coating from one side is different thanthat of the coating from the opposite side. The term “criticalthickness” means a thickness above which a coating material forms acontinuous, uninterrupted layer and below which the coating materialforms discontinuous regions or islands of the coating material ratherthan a continuous layer. The term “subcritical thickness” means athickness below the critical thickness such that the coating materialforms isolated, non-connected regions of the coating material. The term“islanded” means that the coating material is not a continuous layerbut, rather, that the material is deposited to form isolated regions orislands.

For purposes of the following discussion, the invention will bediscussed with reference to use with an architectural transparency, suchas, but not limited to, an insulating glass unit (IGU). As used herein,the term “architectural transparency” refers to any transparency locatedon a building, such as, but not limited to, windows and sky lights.However, it is to be understood that the invention is not limited to usewith such architectural transparencies but could be practiced withtransparencies in any desired field, such as, but not limited to,laminated or non-laminated residential and/or commercial windows,insulating glass units, and/or transparencies for land, air, space,above water and underwater vehicles. Therefore, it is to be understoodthat the specifically disclosed exemplary embodiments are presentedsimply to explain the general concepts of the invention, and that theinvention is not limited to these specific exemplary embodiments.Additionally, while a typical “transparency” can have sufficient visiblelight transmission such that materials can be viewed through thetransparency, in the practice of the invention, the “transparency” neednot be transparent to visible light but may be translucent or opaque.

A non-limiting transparency 10 incorporating features of the inventionis illustrated in FIG. 1. The transparency 10 can have any desiredvisible light, infrared radiation, or ultraviolet radiation transmissionand/or reflection. For example, the transparency 10 can have a visiblelight transmission of any desired amount, e.g., greater than 0% up to100%.

The exemplary transparency 10 of FIG. 1 is in the form of a conventionalinsulating glass unit and includes a first ply 12 with a first majorsurface 14 (No. 1 surface) and an opposed second major surface 16 (No. 2surface). In the illustrated non-limiting embodiment, the first majorsurface 14 faces the building exterior, i.e., is an outer major surface,and the second major surface 16 faces the interior of the building. Thetransparency 10 also includes a second ply 18 having an outer (first)major surface 20 (No. 3 surface) and an inner (second) major surface 22(No. 4 surface) and spaced from the first ply 12. This numbering of theply surfaces is in keeping with conventional practice in thefenestration art. The first and second plies 12, 18 can be connectedtogether in any suitable manner, such as by being adhesively bonded to aconventional spacer frame 24. A gap or chamber 26 is formed between thetwo plies 12, 18. The chamber 26 can be filled with a selectedatmosphere, such as air, or a non-reactive gas such as argon or kryptongas. A solar control coating 30 (or any of the other coatings describedbelow) is formed over at least a portion of one of the plies 12, 18,such as, but not limited to, over at least a portion of the No. 2surface 16 or at least a portion of the No. 3 surface 20. Although, thecoating could also be on the No. 1 surface or the No. 4 surface, ifdesired. Examples of insulating glass units are found, for example, inU.S. Pat. Nos. 4,193,236; 4,464,874; 5,088,258; and 5,106,663.

In the broad practice of the invention, the plies 12, 18 of thetransparency 10 can be of the same or different materials. The plies 12,18 can include any desired material having any desired characteristics.For example, one or more of the plies 12, 18 can be transparent ortranslucent to visible light. By “transparent” is meant having visiblelight transmission of greater than 0% up to 100%. Alternatively, one ormore of the plies 12, 18 can be translucent. By “translucent” is meantallowing electromagnetic energy (e.g., visible light) to pass throughbut diffusing this energy such that objects on the side opposite theviewer are not clearly visible. Examples of suitable materials include,but are not limited to, plastic substrates (such as acrylic polymers,such as polyacrylates; polyalkylmethacrylates, such aspolymethylmethacrylates, polyethylmethacrylates,polypropylmethacrylates, and the like; polyurethanes; polycarbonates;polyalkylterephthalates, such as polyethyleneterephthalate (PET),polypropyleneterephthalates, polybutyleneterephthalates, and the like;polysiloxane-containing polymers; or copolymers of any monomers forpreparing these, or any mixtures thereof); ceramic substrates; glasssubstrates; or mixtures or combinations of any of the above. Forexample, one or more of the plies 12, 18 can include conventionalsoda-lime-silicate glass, borosilicate glass, or leaded glass. The glasscan be clear glass. By “clear glass” is meant non-tinted or non-coloredglass. Alternatively, the glass can be tinted or otherwise coloredglass. The glass can be annealed or heat-treated glass. As used herein,the term “heat treated” means tempered or at least partially tempered.The glass can be of any type, such as conventional float glass, and canbe of any composition having any optical properties, e.g., any value ofvisible transmission, ultraviolet transmission, infrared transmission,and/or total solar energy transmission. By “float glass” is meant glassformed by a conventional float process in which molten glass isdeposited onto a molten metal bath and controllably cooled to form afloat glass ribbon. Examples of float glass processes are disclosed inU.S. Pat. Nos. 4,466,562 and 4,671,155.

The first and second plies 12, 18 can each be, for example, clear floatglass or can be tinted or colored glass or one ply 12, 18 can be clearglass and the other ply 12, 18 colored glass. Although not limiting tothe invention, examples of glass suitable for the first ply 12 and/orsecond ply 18 are described in U.S. Pat. Nos. 4,746,347; 4,792,536;5,030,593; 5,030,594; 5,240,886; 5,385,872; and 5,393,593. The first andsecond plies 12, 18 can be of any desired dimensions, e.g., length,width, shape, or thickness. In one exemplary automotive transparency,the first and second plies can each be 1 mm to 10 mm thick, such as 1 mmto 8 mm thick, such as 2 mm to 8 mm, such as 3 mm to 7 mm, such as 5 mmto 7 mm, such as 6 mm thick. Non-limiting examples of glass that can beused for the practice of the invention include clear glass, Starphire®,Solargreen®, Solextra®, GL-20®, GL35™, Solarbronze®, Solargray® glass,Pacifica® glass, SolarBlue® glass, and Optiblue® glass, all commerciallyavailable from PPG Industries Inc. of Pittsburgh, Pa.

The solar control coating 30 of the invention is deposited over at leasta portion of at least one major surface of one of the glass plies 12,18. In the example shown in FIG. 1, the coating 30 is formed over atleast a portion of the inner surface 16 of the outboard glass ply 12. Asused herein, the term “solar control coating” refers to a coatingcomprised of one or more layers or films that affect the solarproperties of the coated article, such as, but not limited to, theamount of solar radiation, for example, visible, infrared, orultraviolet radiation, reflected from, absorbed by, or passing throughthe coated article; shading coefficient; emissivity, etc. The solarcontrol coating 30 can block, absorb, or filter selected portions of thesolar spectrum, such as, but not limited to, the IR, UV, and/or visiblespectrums.

The solar control coating 30 can be deposited by any conventionalmethod, such as, but not limited to, conventional chemical vapordeposition (CVD) and/or physical vapor deposition (PVD) methods.Examples of CVD processes include spray pyrolysis. Examples of PVDprocesses include electron beam evaporation and vacuum sputtering (suchas magnetron sputter vapor deposition (MSVD)). Other coating methodscould also be used, such as, but not limited to, sol-gel deposition. Inone non-limiting embodiment, the coating 30 can be deposited by MSVD.Examples of MSVD coating devices and methods will be well understood byone of ordinary skill in the art and are described, for example, in U.S.Pat. Nos. 4,379,040; 4,861,669; 4,898,789; 4,898,790; 4,900,633;4,920,006; 4,938,857; 5,328,768; and 5,492,750.

Islanded Metal Layer

An exemplary non-limiting solar control coating 30 of the invention isshown in FIG. 2. This exemplary coating 30 includes a base layer orfirst dielectric layer 40 deposited over at least a portion of a majorsurface of a substrate (e.g., the No. 2 surface 16 of the first ply 12).The first dielectric layer 40 can be a single layer or can comprise morethan one film of antireflective materials and/or dielectric materials,such as, but not limited to, metal oxides, oxides of metal alloys,nitrides, oxynitrides, or mixtures thereof. The first dielectric layer40 can be transparent to visible light. Examples of suitable metaloxides for the first dielectric layer 40 include oxides of titanium,hafnium, zirconium, niobium, zinc, bismuth, lead, indium, tin, andmixtures thereof. These metal oxides can have small amounts of othermaterials, such as manganese in bismuth oxide, tin in indium oxide, etc.Additionally, oxides of metal alloys or metal mixtures can be used, suchas oxides containing zinc and tin (e.g., zinc stannate, defined below),oxides of indium-tin alloys, silicon nitrides, silicon aluminumnitrides, or aluminum nitrides. Further, doped metal oxides, such asantimony or indium doped tin oxides or nickel or boron doped siliconoxides, can be used. The first dielectric layer 40 can be asubstantially single phase film, such as a metal alloy oxide film, e.g.,zinc stannate, or can be a mixture of phases composed of zinc and tinoxides or can be composed of a plurality of films.

For example, the first dielectric layer 40 (whether a single film ormultiple film layer) can have a thickness in the range of 100 Å to 600Å, such as 200 Å to 500 Å, such as 250 Å to 350 Å, such as 250 Å to 310Å, such as 280 Å to 310 Å, such as 300 Å to 330 Å, such as 310 Å to 330Å.

The first dielectric layer 40 can comprise a multi-film structure havinga first film 42, e.g., a metal alloy oxide film, deposited over at leasta portion of a substrate (such as the inner major surface 16 of thefirst ply 12) and a second film 44, e.g., a metal oxide or oxide mixturefilm, deposited over the first metal alloy oxide film 42. In onenon-limiting embodiment, the first film 42 can be a zinc/tin alloyoxide. By “zinc/tin alloy oxide” is meant both true alloys and alsomixtures of the oxides. The zinc/tin alloy oxide can be that obtainedfrom magnetron sputtering vacuum deposition from a cathode of zinc andtin. One non-limiting cathode can comprise zinc and tin in proportionsof 5 wt. % to 95 wt. % zinc and 95 wt. % to 5 wt. % tin, such as 10 wt.% to 90 wt. % zinc and 90 wt. % to 10 wt. % tin. However, other ratiosof zinc to tin could also be used. One suitable metal alloy oxide thatcan be present in the first film 42 is zinc stannate. By “zinc stannate”is meant a composition of Zn_(x)Sn_(1-x)O_(2-x) (Formula 1) where “x”varies in the range of greater than 0 to less than 1. For instance, “x”can be greater than 0 and can be any fraction or decimal between greaterthan 0 to less than 1. For example, where x=⅔, Formula 1 isZn_(2/3)Sn_(1/3)O_(4/3), which is more commonly described as “Zn₂SnO₄”.A zinc stannate-containing film has one or more of the forms of Formula1 in a predominant amount in the film.

The second film 44 can be a metal oxide film, such as zinc oxide. Thezinc oxide film can be deposited from a zinc cathode that includes othermaterials to improve the sputtering characteristics of the cathode. Forexample, the zinc cathode can include a small amount (e.g., up to 10 wt.%, such as up to 5 wt. %) of tin to improve sputtering. In which case,the resultant zinc oxide film would include a small percentage of tinoxide, e.g., up to 10 wt. % tin oxide, e.g., up to 5 wt. % tin oxide. Acoating layer deposited from a zinc cathode having up to 10 wt. % tin(added to enhance the conductivity of the cathode) is referred to hereinas “a zinc oxide film” even though a small amount of tin may be present.The small amount of tin in the cathode (e.g., less than or equal to 10wt. %, such as less than or equal to 5 wt. %) is believed to form tinoxide in the predominantly zinc oxide second film 44.

For example, the first film 42 can be zinc stannate and the second film44 can be zinc oxide (for example, 90 wt. % zinc oxide and 10 wt. % tinoxide). For example, the first film 42 can comprise zinc stannate havinga thickness in the range of 50 Å to 600 Å, such as 50 Å to 500 Å, suchas 75 Å to 350 Å, such as 100 Å to 250 Å, such as 150 Å to 250 Å, suchas 195 Å to 250 Å, such as 200 Å to 250 Å, such as 200 Å to 220 Å.

The second film 44 can comprise zinc oxide having a thickness in therange of 50 Å to 200 Å, such as 75 Å to 200 Å, such as 100 Å to 150 Å,such as 100 Å to 110 Å.

A first heat and/or radiation reflective metallic layer 46 can bedeposited over the first dielectric layer 40. The first reflective layer46 can include a reflective metal, such as, but not limited to, metallicgold, copper, palladium, aluminum, silver, or mixtures, alloys, orcombinations thereof. In one embodiment, the first reflective layer 46comprises a metallic silver layer having a thickness in the range of 50Å to 300 Å, e.g., 50 Å to 250 Å, e.g., 50 Å to 200 Å, such as 70 Å to200 Å, such as 100 Å to 200 Å, such as 125 Å to 200 Å, such as 150 Å to185 Å. The first metallic layer 46 is a continuous layer. By “continuouslayer” is meant that the coating forms a continuous film of the materialand not isolated coating regions.

A first primer layer 48 is located over the first reflective layer 46.The first primer layer 48 can be a single film or a multiple film layer.The first primer layer 48 can include an oxygen-capturing material thatcan be sacrificial during the deposition process to prevent degradationor oxidation of the first reflective layer 46 during the sputteringprocess or subsequent heating processes. The first primer layer 48 canalso absorb at least a portion of electromagnetic radiation, such asvisible light, passing through the coating 30. Examples of materialsuseful for the first primer layer 48 include titanium, silicon, silicondioxide, silicon nitride, silicon oxynitride, nickel-chrome alloys (suchas Inconel), zirconium, aluminum, alloys of silicon and aluminum, alloyscontaining cobalt and chromium (e.g., Stellite®), and mixtures thereof.For example, the first primer layer 48 can be titanium and can have athickness in the range of 5 Å to 50 Å, e.g., 10 Å to 40 Å, e.g., 20 Å to40 Å, e.g., 20 Å to 35 Å.

A second dielectric layer 50 is located over the first reflective layer46 (e.g., over the first primer layer 48). The second dielectric layer50 can comprise one or more metal oxide or metal alloy oxide-containingfilms, such as those described above with respect to the firstdielectric layer 40. For example, the second dielectric layer 50 caninclude a first metal oxide film 52, e.g., a zinc oxide film, depositedover the first primer film 48 and a second metal alloy oxide film 54,e.g., a zinc stannate (Zn₂SnO₄) film, deposited over the first zincoxide film 52. An optional third metal oxide film 56, e.g., another zincoxide layer, can be deposited over the zinc stannate layer.

The second dielectric layer 50 can have a total thickness (e.g., thecombined thicknesses of the layers) is in the range of 50 Å to 1000 Å,e.g., 50 Å to 500 Å, e.g., 100 Å to 370 Å, e.g., 100 Å to 300 Å, e.g.,100 Å to 200 Å, e.g., 150 Å to 200 Å, e.g., 180 Å to 190 Å.

For example, for a multi-film layer, the zinc oxide film 52 (andoptional second zinc oxide film 56, if present) can have a thickness inthe range of 10 Å to 200 Å, e.g., 50 Å to 200 Å, e.g., 60 Å to 150 Å,e.g., 70 Å to 85 Å. The metal alloy oxide layer (zinc stannate) 54 canhave a thickness in the range of 50 Å to 800 Å, e.g., 50 Å to 500 Å,e.g., 100 Å to 300 Å, e.g., 110 Å to 235 Å, e.g., 110 Å to 120 Å.

A subcritical thickness (discontinuous) second metallic layer 58 islocated over the second dielectric layer 50 (e.g., over the second zincoxide film 56, if present, or over the zinc stannate film 54 if not).The metallic material, such as, but not limited to, metallic gold,copper, palladium, aluminum, silver, or mixtures, alloys, orcombinations thereof, is applied at a subcritical thickness such thatisolated regions or islands of the material are formed rather than acontinuous layer of the material. For silver, it has been determinedthat the critical thickness is less than 50 Å, such as less than 40 Å,such as less than 30 Å, such as less than 25 Å. For silver, thetransition between a continuous layer and a subcritical layer occurs inthe range of 25 Å to 50 Å. It is estimated that copper, gold, andpalladium would exhibit similar subcritical behavior in this range. Thesecond metallic layer 58 can include any one or more of the materialsdescribed above with respect to the first reflective layer 46 but thesematerials are not present as a continuous film. In one non-limitingembodiment, the second layer 58 comprises islanded silver with theislands having an effective thickness in the range of 1 Å to 70 Å, e.g.,10 Å to 40 Å, e.g., 10 Å to 35 Å, e.g., 10 Å to 30 Å, e.g., 15 Å to 30Å, e.g., 20 Å to 30 Å, e.g., 25 Å to 30 Å. The subcritical metalliclayer 58 absorbs electromagnetic radiation according to the PlasmonResonance Theory. This absorption depends at least partly on theboundary conditions at the interface of the metallic islands. Thesubcritical metallic layer 58 is not an infrared reflecting layer, likethe first metallic layer 46. The subcritical silver layer 58 is not acontinuous layer. It is estimated that for silver, the metallic islandsor balls of silver metal deposited below the subcritical thickness canhave a height of about 2 nm to 7 nm, such as 5 nm to 7 nm. It isestimated that if the subcritical silver layer could be spread outuniformly, it would have a thickness of about 1.1 nm. It is estimatedthat optically, the discontinuous metal layer behaves as an effectivelayer thickness of 2.6 nm. Depositing the discontinuous metallic layerover zinc stannate rather than zinc oxide appears to increase thevisible light absorbance of the coating, e.g., of the discontinuousmetallic layer.

A second primer layer 60 can be deposited over the second metallic layer58. The second primer layer 60 can be as described above with respect tothe first primer layer 48. In one example, the second primer layer canbe a nickel-chromium alloy (such as Inconel) having a thickness in therange of 5 Å to 50 Å, e.g., 10 Å to 25 Å, e.g., 15 Å to 25 Å, e.g., 15 Åto 22 Å. Since the absorbance of the subcritical material depends atleast partly on the boundary conditions, different primers (e.g., havingdifferent refractive indices) can provide the coating with differentabsorbance spectra and, hence, with different colors.

A third dielectric layer 62 can be deposited over the second metalliclayer 58 (e.g., over the second primer film 60). The third dielectriclayer 62 can also include one or more metal oxide or metal alloyoxide-containing layers, such as discussed above with respect to thefirst and second dielectric layers 40, 50. In one example, the thirddielectric layer 62 is a multi-film layer similar to the seconddielectric layer 50. For example, the third dielectric layer 62 caninclude a first metal oxide layer 64, e.g., a zinc oxide layer, a secondmetal alloy oxide-containing layer 66, e.g., a zinc stannate layerdeposited over the zinc oxide layer 64, and an optional third metaloxide layer 68, e.g., another zinc oxide layer, deposited over the zincstannate layer 66. In one example, both of the zinc oxide layers 64, 68are present and each has a thickness in the range of 50 Å to 200 Å, suchas 75 Å to 150 Å, such as 80 Å to 150 Å, such as 95 Å to 120 Å. Themetal alloy oxide layer 66 can have a thickness in the range of 100 Å to800 Å, e.g., 200 Å to 700 Å, e.g., 300 Å to 600 Å, e.g., 380 Å to 500 Å,e.g., 380 Å to 450 Å.

In one example, the total thickness of the third dielectric layer 62(e.g., the combined thicknesses of the zinc oxide and zinc stannatelayers) is in the range of 200 Å to 1000 Å, e.g., 400 Å to 900 Å, e.g.,500 Å to 900 Å, e.g., 650 Å to 800 Å, e.g., 690 Å to 720 Å.

A third heat and/or radiation reflective metallic layer 70 is depositedover the third dielectric layer 62. The third reflective layer 70 can beof any of the materials discussed above with respect to the firstreflective layer. In one non-limiting example, the third reflectivelayer 70 includes silver and has a thickness in the range of 25 Å to 300Å, e.g., 50 Å to 300 Å, e.g., 50 Å to 200 Å, such as 70 Å to 151 Å, suchas 100 Å to 150 Å, such as 137 Å to 150 Å. The third metallic layer is acontinuous layer.

A third primer layer 72 is located over the third reflective layer 70.The third primer layer 72 can be as described above with respect to thefirst or second primer layers. In one non-limiting example, the thirdprimer layer is titanium and has a thickness in the range of 5 Å to 50Å, e.g., 10 Å to 33 Å, e.g., 20 Å to 30 Å.

A fourth dielectric layer 74 is located over the third reflective layer(e.g., over the third primer layer 72). The fourth dielectric layer 74can be comprised of one or more metal oxide or metal alloyoxide-containing layers, such as those discussed above with respect tothe first, second, or third dielectric layers 40, 50, 62. In onenon-limiting example, the fourth dielectric layer 74 is a multi-filmlayer having a first metal oxide layer 76, e.g., a zinc oxide layer,deposited over the third primer film 72, and a second metal alloy oxidelayer 78, e.g., a zinc stannate layer, deposited over the zinc oxidelayer 76. In one non-limiting embodiment, the zinc oxide layer 76 canhave a thickness in the range of 25 Å to 200 Å, such as 50 Å to 150 Å,such as 60 Å to 100 Å, such as 80 Å to 90 Å. The zinc stannate layer 78can have a thickness in the range of 25 Å to 500 Å, e.g., 50 Å to 500 Å,e.g., 100 Å to 400 Å, e.g., 150 Å to 300 Å, e.g., 150 Å to 200 Å, e.g.,170 Å to 190 Å.

In one non-limiting example, the total thickness of the fourthdielectric layer 74 (e.g., the combined thicknesses of the zinc oxideand zinc stannate layers) is in the range of 100 Å to 800 Å, e.g., 200 Åto 600 Å, e.g., 250 Å to 400 Å, e.g., 250 Å to 270 Å.

An overcoat 80 can be located over the fourth dielectric layer 74. Theovercoat 80 can help protect the underlying coating layers frommechanical and chemical attack. The overcoat 80 can be, for example, ametal oxide or metal nitride layer. For example, the overcoat 80 can betitania having a thickness in the range of 10 Å to 100 Å, such as 20 Åto 80 Å, such as 30 Å to 50 Å, such as 30 Å to 45 Å. Other materialsuseful for the overcoat include other oxides, such as silica, alumina,or a mixture of silica and alumina.

In one non-limiting embodiment, the transparency 10 of the invention hasa percent reflectance (% R) of visible light from the No. 1 surface inthe range of 5% to 50%, such as 20% to 40%, such as 25% to 30%. Thetransparency 10 has a visible light transmittance of greater than 20%,such as greater than 30%, such as greater than 40%. The transparency hasa solar heat gain coefficient (SHGC) of less than 0.3, such as less than0.27, such as less than 0.25.

Unlike prior articles, the ply coated with the coating 30 can betempered or heat treated without adversely impacting upon theperformance characteristics of the article or producing haze. Also, thearticle of the invention has a neutral or moderate reflected color, suchas blue or blue-green, in both reflection and transmission.

The lack of haze upon heating is believed due to the islanded structureof the discontinuous intermediate metallic layer. A side view of asubcritical metallic layer 90 having discontinuous coating regions 91formed on a dielectric layer 92 and covered by a primer layer 94 isshown in FIG. 3. The subcritical metal thickness causes the metalmaterial to form discontinuous regions or islands of metal or metaloxide on the dielectric layer 92. When the primer layer is applied overthe subcritical metal layer, the material of the primer layer covers theislands and can also extend into the gaps between adjacent islands ofthe subcritical metal and contact the underlying layer 92.

The coating 30 of the invention provides various advantages over knowncoatings. For example, the subcritical metallic layer increases thevisible light absorbance of the coating, making the coated articledarker. The combination of the subcritical metallic layer with selectedthicknesses of the dielectric layers can provide the coated article withan asymmetrical reflectance. The color of the article can be tuned intransmission by changing the primer(s) used in the coating. Also, thecoating of the invention is able to be heat treated without introducinghaze.

It is to be understood that the previously described coating 30 is notlimiting to the invention. For example, the subcritical metallic layeris not required to be the second (intermediate) metallic layer in thestack. The subcritical metallic layer could be placed anywhere in thecoating stack. Also, for coating stacks having a plurality of metalliccoating layers, more than one of the metallic layers could be asubcritical metallic layer.

While the above example included two continuous metal layers and onediscontinuous metal layer, it is to be understood that this is just onenon-limiting example. In the broad practice of the invention, thecoating of the invention could include multiple continuous metalliclayers and multiple discontinuous metallic layers. For example, a coatedarticle could include a single subcritical metallic layer locatedbetween two dielectric layers. Or, the coating could include 3 or moremetallic layers, such as 4 or more metallic layers, such as 5 or moremetallic layers, such as 6 or more metallic layers, with at least one ofthe metallic layers being a subcritical metallic layer.

Titanium Primer

Another exemplary coating 130 of the invention is shown in FIG. 4. Thisexemplary coating 130 includes a base layer or first dielectric layer140 deposited over at least a portion of a major surface of a substrate(e.g., the No. 2 surface 16 of the first ply 12). The first dielectriclayer 140 can be similar to the first dielectric layer 40 describedabove. For example, the first dielectric layer 140 can be a single layeror can comprise more than one film of antireflective materials and/ordielectric materials, such as, but not limited to, metal oxides, oxidesof metal alloys, nitrides, oxynitrides, or mixtures thereof. The firstdielectric layer 140 can be transparent to visible light. Examples ofsuitable metal oxides for the first dielectric layer 140 include oxidesof titanium, hafnium, zirconium, niobium, zinc, bismuth, lead, indium,tin, and mixtures thereof. These metal oxides can have small amounts ofother materials, such as manganese in bismuth oxide, tin in indiumoxide, etc. Additionally, oxides of metal alloys or metal mixtures canbe used, such as oxides containing zinc and tin (e.g., zinc stannate,defined below), oxides of indium-tin alloys, silicon nitrides, siliconaluminum nitrides, or aluminum nitrides. Further, doped metal oxides,such as antimony or indium doped tin oxides or nickel or boron dopedsilicon oxides, can be used. The first dielectric layer 140 can be asubstantially single phase film, such as a metal alloy oxide film, e.g.,zinc stannate, or can be a mixture of phases composed of zinc and tinoxides or can be composed of a plurality of films.

For example, the first dielectric layer 140 (whether a single film ormultiple film layer) can have a thickness in the range of 100 Å to 600Å, such as 100 Å to 500 Å, such as 100 Å to 350 Å, such as 150 Å to 300Å, such as 200 Å to 250 Å, such as 210 Å to 220 Å.

The first dielectric layer 140 can comprise a multi-film structurehaving a first film 142, e.g., a metal alloy oxide film, deposited overat least a portion of a substrate (such as the inner major surface 16 ofthe first ply 12) and a second film 144, e.g., a metal oxide or oxidemixture film, deposited over the first metal alloy oxide film 142. Inone non-limiting embodiment, the first film 142 can be zinc stannate.

For example, the first film 142 can be zinc stannate and the second film144 can be zinc oxide (for example, 90 wt. % zinc oxide and 10 wt. % tinoxide). For example, the first film 142 can comprise zinc stannatehaving a thickness in the range of 50 Å to 600 Å, such as 50 Å to 500 Å,such as 75 Å to 350 Å, such as 100 Å to 250 Å, such as 100 Å to 200 Å,such as 100 Å to 150 Å, such as 140 Å to 150 Å.

The second film 144 can comprise zinc oxide having a thickness in therange of 50 Å to 200 Å, such as 50 Å to 150 Å, such as 70 Å to 100 Å.

A first heat and/or radiation reflective metallic layer 146 can bedeposited over the first dielectric layer 140. The first reflectivelayer 146 can include a reflective metal, such as, but not limited to,metallic gold, copper, palladium, silver, or mixtures, alloys, orcombinations thereof. In one embodiment, the first reflective layer 46comprises a metallic silver layer having a thickness in the range of 25Å to 300 Å, e.g., 50 Å to 300 Å, e.g., 50 Å to 250 Å, e.g., 50 Å to 200Å, such as 70 Å to 200 Å, such as 100 Å to 200 Å, such as 120 Å to 180Å.

A first primer layer 148 is located over the first reflective layer 146.The first primer layer 148 can be a single film or a multiple filmlayer. The first primer layer 148 can include an oxygen-capturingmaterial that can be sacrificial during the deposition process toprevent degradation or oxidation of the first reflective layer 146during the sputtering process or subsequent heating processes. The firstprimer layer 148 can also absorb at least a portion of electromagneticradiation, such as visible light, passing through the coating 130.Examples of materials useful for the first primer layer 148 includetitanium, Inconel, Stellite®, and mixtures thereof. For example, thefirst primer layer 148 can have a thickness in the range of 5 Å to 50 Å,e.g., 10 Å to 40 Å, e.g., 20 Å to 40 Å, e.g., 20 Å to 30 Å. In oneexample, the first primer 148 is titanium.

A second dielectric layer 150 is located over the first reflective layer146 (e.g., over the first primer layer 48). The second dielectric layer150 can comprise one or more metal oxide or metal alloy oxide-containingfilms, such as those described above with respect to the firstdielectric layer 140. For example, the second dielectric layer 150 caninclude a first metal oxide film 152, e.g., a zinc oxide film, depositedover the first primer film 148 and a second metal alloy oxide film 154,e.g., a zinc stannate (Zn₂SnO₄) film, deposited over the first zincoxide film 152. An optional third metal oxide film 156, e.g., anotherzinc oxide layer, can be deposited over the zinc stannate layer.

The second dielectric layer 150 can have a total thickness (e.g., thecombined thicknesses of the layers if more than one layer is present) isin the range of 50 Å to 1000 Å, e.g., 50 Å to 500 Å, e.g., 100 Å to 400Å, e.g., 200 Å to 400 Å, e.g., 300 Å to 400 Å, e.g., 350 Å to 400 Å,e.g., 350 Å to 370 Å.

For example, for a multi-film layer, the zinc oxide film 152 (andoptional second zinc oxide film 156, if present) can have a thickness inthe range of 10 Å to 200 Å, e.g., 50 Å to 200 Å, e.g., 50 Å to 150 Å,e.g., 50 Å to 85 Å. The metal alloy oxide layer (zinc stannate) 54 canhave a thickness in the range of 50 Å to 800 Å, e.g., 50 Å to 500 Å,e.g., 100 Å to 300 Å, e.g., 270 Å to 300 Å.

A subcritical (discontinuous) metallic layer 158 is located over thesecond dielectric layer 150 (e.g., over the second zinc oxide film 156,if present, or over the zinc stannate film 154 if not). The secondmetallic layer 158 can include any one or more of the metallic materialsdescribed above with respect to the first reflective layer 146. In onenon-limiting embodiment, the second metallic layer 158 comprisesislanded silver with the islands having an effective thickness in therange of 1 Å to 50 Å, e.g., 10 Å to 40 Å, e.g., 10 Å to 35 Å, e.g., 10 Åto 30 Å, e.g., 15 Å to 30 Å, e.g., 20 Å to 30 Å, e.g., 25 Å to 30 Å.

A second primer layer 160 can be deposited over the second metalliclayer 158. The second primer layer 160 can be as described above withrespect to the first primer layer 148. For example, the second primerlayer can be titanium having a thickness in the range of 5 Å to 50 Å,e.g., 10 Å to 35 Å, e.g., 15 Å to 35 Å, e.g., 20 Å to 30 Å.

A third dielectric layer 162 can be deposited over the second reflectivelayer 158 (e.g., over the second primer layer 160). The third dielectriclayer 162 can also include one or more metal oxide or metal alloyoxide-containing layers, such as discussed above with respect to thefirst and second dielectric layers 140, 150. In one example, the thirddielectric layer 162 is a multi-film layer similar to the seconddielectric layer 150. For example, the third dielectric layer 162 caninclude a first metal oxide layer 164, e.g., a zinc oxide layer, asecond metal alloy oxide-containing layer 166, e.g., a zinc stannatelayer deposited over the zinc oxide layer 164, and an optional thirdmetal oxide layer 168, e.g., another zinc oxide layer, deposited overthe zinc stannate layer 166. In one example, both of the zinc oxidelayers 164, 168 are present and each has a thicknesses in the range of50 Å to 200 Å, such as 75 Å to 150 Å, such as 80 Å to 150 Å, such as 95Å to 100 Å. The metal alloy oxide layer 166 can have a thickness in therange of 100 Å to 800 Å, e.g., 200 Å to 700 Å, e.g., 300 Å to 600 Å,e.g., 500 Å to 600 Å, e.g., 560 Å to 600 Å.

In one example, the total thickness of the third dielectric layer 162(e.g., the combined thicknesses of the zinc oxide and zinc stannatelayers) is in the range of 200 Å to 1000 Å, e.g., 400 Å to 900 Å, e.g.,500 Å to 900 Å, e.g., 650 Å to 800 Å, e.g., 690 Å to 760 Å.

A third heat and/or radiation reflective metallic layer 170 is depositedover the third dielectric layer 162. The third reflective layer 170 canbe of any of the materials discussed above with respect to the first andsecond reflective layers. In one non-limiting example, the thirdreflective layer 170 includes silver and has a thickness in the range of25 Å to 300 Å, e.g., 50 Å to 300 Å, e.g., 50 Å to 200 Å, such as 70 Å to200 Å, such as 100 Å to 200 Å, such as 170 Å to 200 Å.

A third primer layer 172 is located over the third reflective layer 170.The third primer layer 172 can be as described above with respect to thefirst or second primer layers. In one non-limiting example, the thirdprimer layer is titanium and has a thickness in the range of 5 Å to 50Å, e.g., 10 Å to 30 Å, e.g., 20 Å to 30 Å.

A fourth dielectric layer 174 is located over the third reflective layer(e.g., over the third primer film 172). The fourth dielectric layer 174can be comprised of one or more metal oxide or metal alloyoxide-containing layers, such as those discussed above with respect tothe first, second, or third dielectric layers 140, 150, 162. In onenon-limiting example, the fourth dielectric layer 174 is a multi-filmlayer having a first metal oxide layer 176, e.g., a zinc oxide layer,deposited over the third primer film 172, and a second metal alloy oxidelayer 178, e.g., a zinc stannate layer, deposited over the zinc oxidelayer 176. In one non-limiting embodiment, the zinc oxide layer 176 canhave a thickness in the range of 25 Å to 200 Å, such as 50 Å to 150 Å,such as 60 Å to 100 Å, such as 70 Å to 90 Å. The zinc stannate layer 178can have a thickness in the range of 25 Å to 500 Å, e.g., 50 Å to 500 Å,e.g., 100 Å to 400 Å, e.g., 150 Å to 300 Å, e.g., 150 Å to 200 Å, e.g.,170 Å to 200 Å.

In one non-limiting example, the total thickness of the fourthdielectric layer 174 (e.g., the combined thicknesses of the zinc oxideand zinc stannate layers) is in the range of 100 Å to 800 Å, e.g., 200 Åto 600 Å, e.g., 250 Å to 400 Å, e.g., 250 Å to 270 Å.

An overcoat 180 can be located over the fourth dielectric layer 174. Theovercoat 180 can help protect the underlying coating layers frommechanical and chemical attack. The overcoat 180 can be, for example, ametal oxide or metal nitride layer. For example, the overcoat 180 can betitania having a thickness in the range of 10 Å to 100 Å, such as 20 Åto 80 Å, such as 30 Å to 50 Å, such as 30 Å to 40 Å.

Capsule

Another exemplary non-limiting coating 230 of the invention is shown inFIG. 5. This exemplary coating 230 includes a base layer or firstdielectric layer 240 deposited over at least a portion of a majorsurface of a substrate (e.g., the No. 2 surface 16 of the first ply 12).The first dielectric layer 240 can be a single layer or can comprisemore than one film of antireflective materials and/or dielectricmaterials, such as, but not limited to, metal oxides, oxides of metalalloys, nitrides, oxynitrides, or mixtures thereof. The first dielectriclayer 240 can be transparent to visible light. Examples of suitablemetal oxides for the first dielectric layer 240 include oxides oftitanium, hafnium, zirconium, niobium, zinc, bismuth, lead, indium, tin,and mixtures thereof. These metal oxides can have small amounts of othermaterials, such as manganese in bismuth oxide, tin in indium oxide, etc.Additionally, oxides of metal alloys or metal mixtures can be used, suchas oxides containing zinc and tin (e.g., zinc stannate, defined below),oxides of indium-tin alloys, silicon nitrides, silicon aluminumnitrides, or aluminum nitrides. Further, doped metal oxides, such asantimony or indium doped tin oxides or nickel or boron doped siliconoxides, can be used. The first dielectric layer 240 can be asubstantially single phase film, such as a metal alloy oxide film, e.g.,zinc stannate, or can be a mixture of phases composed of zinc and tinoxides or can be composed of a plurality of films.

For example, the first dielectric layer 240 (whether a single film ormultiple film layer) can have a thickness in the range of 100 Å to 600Å, such as 200 Å to 500 Å, such as 250 Å to 350 Å, such as 250 Å to 310Å, such as 280 Å to 310 Å, such as 290 Å to 300 Å.

The first dielectric layer 240 can comprise a multi-film structurehaving a first film 242, e.g., a metal alloy oxide film, deposited overat least a portion of a substrate (such as the inner major surface 16 ofthe first ply 12) and a second film 244, e.g., a metal oxide or oxidemixture film, deposited over the first metal alloy oxide film 242. Inone non-limiting embodiment, the first film 242 can be zinc stannate.

For example, the first film 242 can be zinc stannate and the second film244 can be zinc oxide (for example, 90 wt. % zinc oxide and 10 wt. % tinoxide). For example, the first film 242 can comprise zinc stannatehaving a thickness in the range of 50 Å to 600 Å, such as 50 Å to 500 Å,such as 75 Å to 350 Å, such as 100 Å to 250 Å, such as 150 Å to 250 Å,such as 200 Å to 250 Å, such as 200 Å to 240 Å.

The second film 244 can comprise zinc oxide having a thickness in therange of 50 Å to 200 Å, such as 50 Å to 175 Å, such as 50 Å to 150 Å,such as 50 Å to 100 Å.

A first heat and/or radiation reflective metallic layer 246 can bedeposited over the first dielectric layer 240. The first reflectivelayer 246 can include a reflective metal, such as, but not limited to,metallic gold, copper, palladium, silver, or mixtures, alloys, orcombinations thereof. In one embodiment, the first reflective layer 246comprises a metallic silver layer having a thickness in the range of 25Å to 300 Å, e.g., 50 Å to 300 Å, e.g., 50 Å to 250 Å, e.g., 50 Å to 200Å, such as 70 Å to 200 Å, such as 100 Å to 200 Å, such as 140 Å to 180Å.

A first primer layer 248 is located over the first reflective layer 246.The first primer layer 248 can be a single film or a multiple filmlayer. The first primer layer 248 can include an oxygen-capturingmaterial that can be sacrificial during the deposition process toprevent degradation or oxidation of the first reflective layer 246during the sputtering process or subsequent heating processes. The firstprimer layer 248 can also absorb at least a portion of electromagneticradiation, such as visible light, passing through the coating 230.Examples of materials useful for the first primer layer 248 includetitanium, Inconel, Stellite®, and mixtures thereof. For example, thefirst primer layer 248 can have a thickness in the range of 5 Å to 50 Å,e.g., 10 Å to 40 Å, e.g., 15 Å to 30 Å, e.g., 16 Å to 30 Å.

A second dielectric layer 250 is located over the first reflective layer246 (e.g., over the first primer layer 248). The second dielectric layer250 can comprise one or more metal oxide or metal alloy oxide-containingfilms, such as those described above with respect to the firstdielectric layer 240. For example, the second dielectric layer 250 caninclude a first metal oxide film 252, e.g., a zinc oxide film, depositedover the first primer film 248 and a second metal alloy oxide film 254,e.g., a zinc stannate (Zn₂SnO₄) film, deposited over the first zincoxide film 252. An optional third metal oxide film 256, e.g., anotherzinc oxide layer, can be deposited over the zinc stannate layer.

The second dielectric layer 250 can have a total thickness (e.g., thecombined thicknesses of the layers) in the range of 50 Å to 1000 Å,e.g., 50 Å to 500 Å, e.g., 100 Å to 370 Å, e.g., 100 Å to 300 Å, e.g.,100 Å to 250 Å, e.g., 200 Å to 230 Å.

For example, for a multi-film layer, the zinc oxide film 252 (andoptional third zinc oxide film 256, if present) can have a thickness inthe range of 10 Å to 200 Å, e.g., 50 Å to 200 Å, e.g., 60 Å to 150 Å,e.g., 75 Å to 85 Å. The metal alloy oxide layer (zinc stannate) 254 canhave a thickness in the range of 50 Å to 800 Å, e.g., 50 Å to 500 Å,e.g., 100 Å to 200 Å, e.g., 155 Å to 200 Å.

An absorbing layer 257 is located over the second dielectric layer 250(e.g., over the third zinc oxide film 256, if present, or over the zincstannate film 254 if not). The absorbing layer 257 can be a multilayerstructure having a first absorbing layer 259, a metallic layer 261, anda second absorbing layer 263. The first and second absorbing layers 259,263 can be the same or different materials. Material suitable for theabsorbing layers includes metal or silicon oxide or nitrides. Forexample, the first and second absorbing layers 259, 265 can be siliconnitride. The first absorbing layer 259 can have a thickness in the rangeof 10 Å to 200 Å, e.g., 50 Å to 200 Å, e.g., 60 Å to 150 Å, e.g., 80 Åto 90 Å. The second absorbing layer 263 can also be silicon nitride andcan have a thickness in the range of 10 Å to 200 Å, e.g., 50 Å to 200 Å,e.g., 60 Å to 150 Å, e.g., 75 Å to 100 Å.

The metallic layer 261 can be a subcritical thickness layer as describedabove. In one example, the metallic layer 261 is a cobalt-chromium alloy(such as Stellite®) and has a thickness in the range of 1 Å to 50 Å,e.g., 10 Å to 40 Å, e.g., 10 Å to 35 Å, e.g., 10 Å to 30 Å, e.g., 15 Åto 30 Å, e.g., 20 Å to 30 Å, e.g., 25 Å to 30 Å.

A third dielectric layer 262 can be deposited over the absorbing layer257. The third dielectric layer 262 can also include one or more metaloxide or metal alloy oxide-containing layers, such as discussed abovewith respect to the first and second dielectric layers 240, 250. In oneexample, the third dielectric layer 262 is a multi-film layer similar tothe second dielectric layer 250. For example, the third dielectric layer262 can include an optional first metal oxide layer 264, e.g., a zincoxide layer, a second metal alloy oxide-containing layer 266, e.g., azinc stannate layer deposited over the zinc oxide layer 264 (ifpresent), and an optional third metal oxide layer 268, e.g., anotherzinc oxide layer, deposited over the zinc stannate (second) layer 266.In one example, the first zinc oxide layer 264 (if present) and thethird zinc oxide layer 268 can each have a thickness in the range of 50Å to 200 Å, such as 75 Å to 150 Å, such as 80 Å to 150 Å, such as 95 Åto 105 Å. The metal alloy oxide layer (second) 266 can have a thicknessin the range of 100 Å to 800 Å, e.g., 200 Å to 700 Å, e.g., 300 Å to 600Å, e.g., 380 Å to 500 Å, e.g., 420 Å to 450 Å.

In one example, the total thickness of the third dielectric layer 262(e.g., the combined thicknesses of the zinc oxide and zinc stannatelayers) is in the range of 200 Å to 1000 Å, e.g., 400 Å to 900 Å, e.g.,500 Å to 900 Å, e.g., 500 Å to 600 Å, e.g., 525 Å to 550 Å.

A third heat and/or radiation reflective metallic layer 270 is depositedover the third dielectric layer 262. The third reflective layer 270 canbe of any of the materials discussed above with respect to the first andsecond reflective layers. In one non-limiting example, the thirdreflective layer 270 includes silver and has a thickness in the range of25 Å to 300 Å, e.g., 50 Å to 300 Å, e.g., 50 Å to 200 Å, such as 70 Å to150 Å, such as 100 Å to 150 Å, such as 128 Å to 150 Å.

A third primer layer 272 is located over the third reflective layer 270.The third primer layer 272 can be as described above with respect to thefirst or second primer layers. In one non-limiting example, the thirdprimer layer is titanium and has a thickness in the range of 5 Å to 50Å, e.g., 10 Å to 30 Å, e.g., 17 Å to 30 Å.

A fourth dielectric layer 274 is located over the third reflective layer(e.g., over the third primer layer 272). The fourth dielectric layer 274can be comprised of one or more metal oxide or metal alloyoxide-containing layers, such as those discussed above with respect tothe first, second, or third dielectric layers 240, 250, 262. In onenon-limiting example, the fourth dielectric layer 274 is a multi-filmlayer having a first metal oxide layer 276, e.g., a zinc oxide layer,deposited over the third primer film 272, and a second metal alloy oxidelayer 278, e.g., a zinc stannate layer, deposited over the zinc oxidelayer 276. In one non-limiting embodiment, the zinc oxide layer 276 canhave a thickness in the range of 25 Å to 200 Å, such as 50 Å to 150 Å,such as 60 Å to 100 Å, such as 60 Å to 70 Å. The zinc stannate layer 78can have a thickness in the range of 25 Å to 500 Å, e.g., 50 Å to 500 Å,e.g., 100 Å to 400 Å, e.g., 150 Å to 300 Å, e.g., 150 Å to 200 Å, e.g.,180 Å to 190 Å.

In one non-limiting example, the total thickness of the fourthdielectric layer 274 (e.g., the combined thickness of the zinc oxide andzinc stannate layers) is in the range of 100 Å to 800 Å, e.g., 200 Å to600 Å, e.g., 250 Å to 400 Å, e.g., 250 Å to 270 Å.

An overcoat 280 can be located over the fourth dielectric layer 274. Theovercoat 280 can help protect the underlying coating layers frommechanical and chemical attack. The overcoat 280 can be, for example, ametal oxide or metal nitride layer. For example, the overcoat 280 can betitania having a thickness in the range of 10 Å to 100 Å, such as 20 Åto 80 Å, such as 30 Å to 50 Å, such as 30 Å to 40 Å.

Dual Primer

Another exemplary non-limiting coating 330 of the invention is shown inFIG. 6. This exemplary coating 330 includes a base layer or firstdielectric layer 340 deposited over at least a portion of a majorsurface of a substrate (e.g., the No. 2 surface 16 of the first ply 12).The first dielectric layer 340 can be similar to the first dielectriclayer 40 described above. For example, the first dielectric layer 340can be a single layer or can comprise more than one film ofantireflective materials and/or dielectric materials, such as, but notlimited to, metal oxides, oxides of metal alloys, nitrides, oxynitrides,or mixtures thereof. The first dielectric layer 340 can be transparentto visible light. Examples of suitable metal oxides for the firstdielectric layer 340 include oxides of titanium, hafnium, zirconium,niobium, zinc, bismuth, lead, indium, tin, and mixtures thereof. Thesemetal oxides can have small amounts of other materials, such asmanganese in bismuth oxide, tin in indium oxide, etc. Additionally,oxides of metal alloys or metal mixtures can be used, such as oxidescontaining zinc and tin (e.g., zinc stannate, defined below), oxides ofindium-tin alloys, silicon nitrides, silicon aluminum nitrides, oraluminum nitrides. Further, doped metal oxides, such as antimony orindium doped tin oxides or nickel or boron doped silicon oxides, can beused. The first dielectric layer 340 can be a substantially single phasefilm, such as a metal alloy oxide film, e.g., zinc stannate, or can be amixture of phases composed of zinc and tin oxides or can be composed ofa plurality of films.

For example, the first dielectric layer 340 (whether a single film ormultiple film layer) can have a thickness in the range of 100 Å to 800Å, such as 100 Å to 600 Å, such as 200 Å to 600 Å, such as 400 Å to 500Å, such as 440 Å to 500 Å.

The first dielectric layer 340 can comprise a multi-film structurehaving a first film 342, e.g., a metal alloy oxide film, deposited overat least a portion of a substrate (such as the inner major surface 16 ofthe first ply 12) and a second film 344, e.g., a metal oxide or oxidemixture film, deposited over the first metal alloy oxide film 342. Inone non-limiting embodiment, the first film 342 can be zinc stannate.

For example, the first film 342 can be zinc stannate and the second film344 can be zinc oxide (for example, 90 wt. % zinc oxide and 10 wt. % tinoxide). For example, the first film 342 can comprise zinc stannatehaving a thickness in the range of 50 Å to 600 Å, such as 50 Å to 500 Å,such as 75 Å to 400 Å, such as 200 Å to 400 Å, such as 300 Å to 400 Å,such as 355 Å to 400 Å.

The second film 344 can comprise zinc oxide having a thickness in therange of 50 Å to 200 Å, such as 50 Å to 150 Å, such as 85 Å to 100 Å.

A first heat and/or radiation reflective metallic layer 346 can bedeposited over the first dielectric layer 340. The first reflectivelayer 346 can include a reflective metal, such as, but not limited to,metallic gold, copper, silver, or mixtures, alloys, or combinationsthereof. In one embodiment, the first reflective layer 346 comprises ametallic silver layer having a thickness in the range of 25 Å to 300 Å,e.g., 50 Å to 300 Å, e.g., 50 Å to 250 Å, e.g., 50 Å to 200 Å, such as70 Å to 200 Å, such as 70 Å to 100 Å, such as 73 Å to 100 Å.

A first primer layer 348 is located over the first reflective layer 346.The first primer layer 348 can be a single film or a multiple filmlayer. The first primer layer 348 can include an oxygen-capturingmaterial that can be sacrificial during the deposition process toprevent degradation or oxidation of the first reflective layer 346during the sputtering process or subsequent heating processes. The firstprimer layer 348 can also absorb at least a portion of electromagneticradiation, such as visible light, passing through the coating 330.Examples of materials useful for the first primer layer 348 includetitanium, Inconel, Stellite®, and mixtures thereof. For example, thefirst primer layer 348 can be a multi-film layer having a first primerfilm 349 and a second primer film 351. The first and second primer films349, 351 are typically of different materials. For example, the firstprimer film 349 can be Inconel having a thickness in the range of 1 Å to10 Å, e.g., 1 Å to 5 Å. The second primer film 351 can be titaniumhaving a thickness in the range of 5 Å to 20 Å, e.g., 10 Å to 15 Å.

A second dielectric layer 350 is located over the first reflective layer346 (e.g., over the first primer layer 348). The second dielectric layer350 can comprise one or more metal oxide or metal alloy oxide-containingfilms, such as those described above with respect to the firstdielectric layer 340. For example, the second dielectric layer 350 caninclude a first metal oxide film 352, e.g., a zinc oxide film, depositedover the first primer film 348 and a second metal alloy oxide film 354,e.g., a zinc stannate (Zn₂SnO₄) film, deposited over the first zincoxide film 352. An optional third metal oxide film 356, e.g., anotherzinc oxide layer, can be deposited over the zinc stannate layer.

The second dielectric layer 350 can have a total thickness (e.g., thecombined thicknesses of the layers if more than one layer is present) isin the range of 50 Å to 1000 Å, e.g., 50 Å to 800 Å, e.g., 100 Å to 800Å, e.g., 200 Å to 800 Å, e.g., 500 Å to 700 Å, e.g., 650 Å to 700 Å.

For example, for a multi-film layer, the zinc oxide film 352 (andoptional third zinc oxide film 356, if present) can have a thickness inthe range of 10 Å to 200 Å, e.g., 50 Å to 200 Å, e.g., 50 Å to 150 Å,e.g., 50 Å to 75 Å. The metal alloy oxide layer (zinc stannate) 54 canhave a thickness in the range of 50 Å to 800 Å, e.g., 50 Å to 500 Å,e.g., 100 Å to 500 Å, e.g., 400 Å to 500 Å.

A reflective metallic layer 358 is located over the second dielectriclayer 350 (e.g., over the third zinc oxide film 356, if present, or overthe zinc stannate film 354 if not). In one non-limiting embodiment, thesecond reflective layer 358 comprises silver having a thickness in therange of 50 Å to 300 Å, e.g., 100 Å to 200 Å, e.g., 150 Å to 200 Å,e.g., 170 Å to 200 Å.

A second primer layer 372 can be deposited over the second reflectivelayer 358. The second primer layer 372 can be as described above withrespect to the first primer layer 348. For example, the second primerlayer 372 can be a multi-film layer having a first primer film 371 and asecond primer film 373. The first and second primer films 371, 373 aretypically of different materials. For example, the first primer film 371can be Inconel having a thickness in the range of 1 Å to 15 Å, e.g., 5 Åto 10 Å. The second primer film 373 can be titanium having a thicknessin the range of 5 Å to 20 Å, e.g., 10 Å to 15 Å.

A third dielectric layer 374 can be deposited over the second reflectivelayer 358 (e.g., over the second primer film 372). The third dielectriclayer 374 can also include one or more metal oxide or metal alloyoxide-containing layers, such as discussed above with respect to thefirst and second dielectric layers 340, 350. In one example, the thirddielectric layer 374 is a multi-film layer similar to the seconddielectric layer 350. In one non-limiting example, the third dielectriclayer 374 is a multi-film layer having a first metal oxide layer 376,e.g., a zinc oxide layer, deposited over the second primer layer 372,and a second metal alloy oxide layer 378, e.g., a zinc stannate layer,deposited over the zinc oxide layer 376. In one non-limiting embodiment,the zinc oxide layer 376 can have a thickness in the range of 25 Å to200 Å, such as 50 Å to 150 Å, such as 100 Å to 150 Å. The zinc stannatelayer 378 can have a thickness in the range of 25 Å to 500 Å, e.g., 50 Åto 500 Å, e.g., 100 Å to 400 Å, e.g., 200 Å to 350 Å, e.g., 300 Å to 350Å, e.g., 320 Å to 350 Å.

In one non-limiting example, the total thickness of the third dielectriclayer 374 (e.g., the combined thicknesses of the zinc oxide and zincstannate layers) is in the range of 100 Å to 800 Å, e.g., 200 Å to 600Å, e.g., 250 Å to 500 Å, e.g., 470 Å to 500 Å.

An overcoat 380 can be located over the third dielectric layer 374. Theovercoat 380 can help protect the underlying coating layers frommechanical and chemical attack. The overcoat 380 can be, for example, ametal oxide or metal nitride layer. For example, the overcoat 380 can betitania having a thickness in the range of 10 Å to 100 Å, such as 20 Åto 80 Å, such as 30 Å to 50 Å, such as 30 Å to 40 Å.

Nanocomposite Layer

As described above, the subcritical silver layer can be applied onto asurface and then another layer, such as a metal oxide or metal layer canbe applied over the subcritical silver layer to essentially encapsulateand protect the silver islands. However, in another embodiment of theinvention, a nanocomposite layer can be deposited with a nanocrystallinemetallic phase embedded or incorporated within a dielectric matrixphase. FIG. 7 shows a nanocomposite layer 382 having a first material384 with metallic nanoparticles 386 incorporated into the first material382 deposited on a substrate 388. This nanocomposite layer 382 couldtake the place of one or more metallic silver layers in a solar controlcoating, for example, such as any of the coatings described above. Sucha nanocomposite layer 382 could be provided by conventional reactivesputtering using a target having a first material and at least onesecond material. The first material can be a material that has arelatively stronger tendency to nitride or oxidize than the secondmaterial. These materials could be present either as alloys or as acomposite target. For example, the first material could be Cr, Al, Ti,or Si. The second material could be a noble metal, such as Ag, Cu, or Auor a transition metal including Fe, Ni, or Co. When the target issputtered, for example, in an oxygen containing atmosphere, the firstmaterial oxidizes and forms a dielectric matrix phase and the secondmaterial is contained within the phase, such as in the form of metalnanoparticles. The nanocomposite layer 382 can be adjusted byappropriate selection of the reactive gas, sputtering voltage, etc., toform a nanocomposite layer of a desired thickness. This nanocompositelayer 382 having the metallic particles 386 embedded within the firstmaterial 384 can better withstand the high temperatures associated withheat treating or tempering than coatings with continuous metallic films.

Small Band Gap Semiconductor Materials as Absorber Layer

In some applications, it may be desirable to modify particulartransmitted color without affecting the solar control performance of thecoating. One way to do this would be by the use of integrating asemiconductor material into a solar control coating that has a band gapedge in the visible region of the electromagnetic spectrum. As will beappreciated by one skilled in the art, at the edge of a semiconductorband gap, shorter wave length radiation is absorbed by the semiconductormaterial while longer wavelength energy is transmitted through thematerial. That is, the material is transparent to radiation above theedge of the band gap. By selecting a material having a band gap edge inthe visible region, one can select the wavelength of electromagneticradiation that is absorbed or passes through the semiconductor material.By using semiconductor materials with small band gaps, such as but notlimited to, germanium or germanium-based alloys, the absorption edge canbe placed near the long-wavelength side of the visible spectrum. In thisway, the optical transmission can be reduced without absorbing near orfar infrared radiation, minimizing unnecessary heating of the glass intoabsorption. This semiconductor material can be placed within aconventional solar control coating, such as between two silver layers,above a silver layer, below a silver layer, or anywhere else within thestack.

The following Examples illustrate various embodiments of the invention.However, it is to be understood that the invention is not limited tothese specific embodiments.

EXAMPLES

In the following Examples, “Rf” refers to the film side reflectance,“Rg” refers to the glass side reflectance, “T” refers to thetransmittance through the article, “Rg60” refers to the glass sidereflectance at a 60 degree angle, “Rx” refers to the exteriorreflectance of a standard IGU from the No. 1 surface, “Rint” refers tothe reflectance of the IGU from the inside (No. 4) surface, “VLT” refersto the visible light transmittance, and “SHGC” refers to the solar heatgain coefficient. A “standard IGU” has an outer ply of 6 mm thick glass,an inner ply of 6 mm glass, a 0.5 inch (1.27 cm) gap filled with air,with the coating on the No. 2 surface. “S.C.” means “subcritical”thickness (that is, the layer was not a continuous layer but wasdeposited to form discontinuous coating regions.)

In the following examples, “heat treated” means that the coatedsubstrate was heated in a box furnace to a temperature of 1,185° F. tosimulate tempering and then air cooled to room temperature before theoptical characteristics were measured.

The color coordinates a*, b*, and L* are those of the conventional CIE(1931) and CIELAB systems that will be understood by one of ordinaryskill in the art.

In order to model the response of the subcritical layer structure toelectromagnetic radiation so that the optical properties of the entirestack can be optimized and controlled, the subcritical layer can bemodeled as two idealized layers. These idealized layers have uniformoptical properties (i.e., index of refraction (n) and extinctionco-efficient (k)) through their thickness, as do the other layers in thestack. Thus, the thicknesses referred to in the examples are thethicknesses of these idealized layers and are meaningful in the contextof calculating the optical response of a given coating stack containingthese layers.

Also, the thickness values associated with the “subcritical” layers inthe following Examples are “effective thickness” calculated based on areference coating speed that is slower than the actual coating speed ofthe commercial coater. For example, a silver layer is applied onto asubstrate at the same coating rate as a commercial coater but at areduced line speed (reference coating speed) compared to the commercialcoater. The thickness of the coating deposited at the reference coatingspeed is measured and then the “effective thickness” for a coatingdeposited at the same coating rate but at the faster line speed of thecommercial coater is extrapolated. For example, if a particular coatingrate provides a silver coating of 250 Å at reference coating speed thatis one-tenth the line speed of the commercial coater, then the“effective thickness” of the silver layer at the same coating rate butat the commercial coater line speed (i.e., ten time faster than thereference coating run) is extrapolated to be 25 Å (i.e., one tenth thethickness). However, as will be appreciated, the silver layer at thiseffective thickness (below the subcritical thickness) would not be acontinuous layer but rather would be a discontinuous layer havingdiscontinuous regions of silver material.

Example 1

A coating was deposited by a conventional MSVD coater (commerciallyavailable from Applied Materials) on a 6 mm piece of clear glass. Thecoated glass had the following structure:

titania 40 Å zinc stannate 190 Å zinc oxide (90/10) 80 Å titanium 30 Åsilver 150 Å zinc oxide 120 Å zinc stannate 450 Å zinc oxide 120 ÅInconel 22 Å S.C. silver 25 Å zinc stannate 110 Å zinc oxide 70 Åtitanium 30 Å silver 180 Å zinc oxide 110 Å zinc stannate 200 Å clearglass 6 mm

This coated glass was heat treated as described above and had theoptical characteristics shown in Table 1 below. The article wasincorporated into a standard IGU as the outer ply (the inner ply wasuncoated 6 mm clear glass) and had the optical characteristics set forthin Table 2 below.

Example 2

A coating was deposited by a conventional Airco MSVD coater on a 6 mmpiece of Starphire® glass. The coated glass had the following structure:

titania 40 Å zinc stannate 170 Å zinc oxide (90/10) 80 Å titanium 20 Åsilver 150 Å zinc oxide 120 Å zinc stannate 480 Å zinc oxide 120 ÅInconel 22 Å S.C. silver 25 Å zinc stannate 110 Å zinc oxide 70 Åtitanium 20 Å silver 180 Å zinc oxide 110 Å zinc stannate 220 ÅStarphire ® glass 6 mm

This coated glass was heat treated as described above and had theoptical characteristics shown in Table 1 below. The article wasincorporated into a standard IGU as the outer ply (the inner ply wasuncoated 6 mm Starphire® glass) and had the optical characteristics setforth in Table 2 below.

Example 3

A coating was deposited by a conventional Airco MSVD coater on a 6 mmpiece of Optiblue® glass. The coated glass had the following structure:

titania 40 Å zinc stannate 170 Å zinc oxide (90/10) 80 Å titanium 20 Åsilver 150 Å zinc oxide 120 Å zinc stannate 480 Å zinc oxide 120 ÅInconel 22 Å S.C. silver 25 Å zinc stannate 110 Å zinc oxide 70 Åtitanium 20 Å silver 180 Å zinc oxide 110 Å zinc stannate 220 ÅOptiblue ® glass 6 mm

This coated glass was heat treated as described above and had theoptical characteristics shown in Table 1 below. The article wasincorporated into a standard IGU as the outer ply (the inner ply wasuncoated 6 mm Starphire® glass) and had the optical characteristics setforth in Table 2 below.

Example 4

A coating was deposited by a conventional Airco MSVD coater on a 6 mmpiece of clear glass. The coated glass had the following structure:

titania 40 Å zinc stannate 200 Å zinc oxide (90/10) 70 Å titanium 30 Åsilver 170 Å zinc oxide 100 Å zinc stannate 560 Å zinc oxide 100 Åtitanium 30 Å S.C. silver 25 Å Zinc oxide 50 Å zinc stannate 270 Å zincoxide 50 Å titanium 30 Å silver 120 Å zinc oxide 70 Å zinc stannate 140Å clear glass 6 mm

This coated glass was heat treated as described above and had theoptical characteristics shown in Table 1 below. The article wasincorporated into a standard IGU as the outer ply (the inner ply wasuncoated 6 mm clear glass) and had the optical characteristics set forthin Table 2 below.

Example 5

A coating was deposited by a conventional Airco MSVD coater on a 6 mmpiece of clear glass. The coated glass had the following structure:

titania 40 Å zinc stannate 170 Å zinc oxide (90/10) 80 Å titanium 30 Åsilver 137 Å zinc oxide 95 Å zinc stannate 380 Å zinc oxide 95 Å Inconel15 Å S.C. silver 30 Å zinc stannate 235 Å zinc oxide 85 Å titanium 30 Åsilver 125 Å zinc oxide 100 Å zinc stannate 200 Å clear glass 6 mm

This coated glass was heat treated as described above and had theoptical characteristics shown in Table 1 below. The article wasincorporated into a standard IGU as the outer ply (the inner ply wasuncoated 6 mm clear glass) and had the optical characteristics set forthin Table 2 below.

Example 6

A coating was deposited by a conventional Airco MSVD coater on a 6 mmpiece of clear glass. The coated glass had the following structure:

titania 40 Å zinc stannate 320 Å zinc oxide (90/10) 150 Å titanium 15 ÅInconel 15 Å silver 170 Å zinc oxide 75 Å zinc stannate 500 Å zinc oxide75 Å titanium 15 Å Inconel 5 Å silver 73 Å zinc oxide 85 Å zinc stannate355 Å clear glass 6 mm

This coated glass was not heat treated and had the opticalcharacteristics shown in Table 1 below. The article was incorporatedinto a standard IGU as the outer ply (the inner ply was uncoated 6 mmclear glass) and had the optical characteristics set forth in Table 2below.

Example 7

A coating was deposited by a conventional Airco MSVD coater on a 6 mmpiece of clear glass. The coated glass had the following structure:

titania 40 Å zinc stannate 190 Å zinc oxide (90/10) 60 Å titanium 17 Åsilver 128 Å zinc oxide 105 Å zinc stannate 420 Å zinc oxide 120 Åsilicon nitride 100 Å Stellite ® 30 Å silicon nitride 80 Å zinc stannate155 Å zinc oxide 75 Å titanium 16 Å silver 140 Å zinc oxide 50 Å zincstannate 240 Å clear glass 6 mm

This coated glass was not heat treated and had the opticalcharacteristics shown in Table 1 below. The article was incorporatedinto a standard IGU as the outer ply (the inner ply was uncoated 6 mmclear glass) and had the optical characteristics set forth in Table 2below.

Example 8

A coating was deposited by a conventional Airco MSVD coater on a 6 mmpiece of clear glass. The coated glass had the following structure:

titania 40 Å zinc stannate 180 Å zinc oxide (90/10) 70 Å titanium 30 Åsilver 128 Å zinc oxide 105 Å zinc stannate 420 Å zinc oxide 120 Åsilicon nitride 100 Å Stellite ® 30 Å silicon nitride 80 Å zinc stannate155 Å zinc oxide 75 Å titanium 30 Å silver 140 Å zinc oxide 50 Å zincstannate 240 Å clear glass 6 mm

This coated glass was heat treated as described above and had theoptical characteristics shown in Table 1 below. The article wasincorporated into a standard IGU as the outer ply (the inner ply wasuncoated 6 mm clear glass) and had the optical characteristics set forthin Table 2 below.

Example 9

A coating was deposited by a conventional Airco MSVD coater on a 6 mmpiece of clear glass. The coated glass had the following structure:

titania 43 Å zinc stannate 196 Å zinc oxide (90/10) 81 Å titanium 33 Åsilver 151 Å zinc oxide 120 Å zinc stannate 448 Å zinc oxide 120 ÅInconel 22 Å S.C. silver 26 Å zinc stannate 116 Å zinc oxide 70 Åtitanium 35 Å silver 182 Å zinc oxide 110 Å zinc stannate 198 Å clearglass 6 mm

TABLE 1 Example No. RfL* Rfa* Rfb* RgL* Rga* Rgb* TL* Ta* Tb* Rg60L*Rg60a* Rg60b* 1 31.4 −3.15 −22.31 61.58 −0.86 −0.54 73.97 −4.61 −3.3263.10 −7.10 −1.30 2 34.6 6.2 19.3 62.6 1.0 −0.9 75.2 4.0 2.2 NA NA NA 331.6 −5.1 −20.7 49.6 0.2 −6.9 65.4 −3.8 −7.3 NA NA NA 4 44.5 −0.5 −9.758.6 −3.2 0.4 76.3 −6.3 −6.0 NA NA NA 5 30.4 −6.7 −9.5 44 −1.7 −3.5 84.9−3.0 0.9 NA NA NA 6 57.53 −1.65 −3.83 58.19 −1.69 2.07 72.23 −3.46 −3.57NA NA NA 7 31.0 −1.8 −12.1 58.1 −1.3 1.7 73.0 −5.7 −0.7 NA NA NA 8 33.2−1.3 −12.1 61.5 −2.2 2.2 72.2 −4.5 −1.4 NA NA NA

TABLE 2 Example No. RxL* Rxa* Rxb* RintL* Rinta* Rintb* TL* Ta* Tb* RxRint VLT SHGC 1 63.07 −1.16 −0.87 44.02 −2.57 −13 70.75 −5.81 −3.53 3214 42 0.232 2 64.2 0.4 −1.0 45.8 −3.9 −12.2 72.6 −4.1 −2.3 33 15 440.234 3 50.8 0.8 −8.2 43.6 −2.6 −13.2 62.4 −5.3 −7.1 19 13 31 0.2 4 60.7−3.6 −0.5 51.8 −1.9 −6.9 73.4 −7.5 −5.6 29 20 45 0.27 5 NA NA NA NA NANA NA NA NA NA NA NA NA 6 60.0 −2.2 1.4 61.1 −3.6 −2.7 69.8 −4.5 −3.5 2829 40 0.240 7 59.4 −1.2 1.0 43.6 −1.5 −7.6 69.7 −6.8 −0.7 28 14 40 0.238 62.5 −1.8 1.4 44.6 −1.1 −8.2 69.1 −5.7 −0.9 31 14 39 0.23

It will be readily appreciated by those skilled in the art thatmodifications may be made to the invention without departing from theconcepts disclosed in the foregoing description. Accordingly, theparticular embodiments described in detail herein are illustrative onlyand are not limiting to the scope of the invention, which is to be giventhe full breadth of the appended claims and any and all equivalentsthereof.

What is claimed is:
 1. A coated article, comprising: a substrate; and acoating over at least a portion of the substrate, the coatingcomprising: a first dielectric layer formed over at least a portion ofthe substrate, wherein the first dielectric layer comprises a first filmand a second film; a first metallic layer over the first dielectriclayer; a first primer layer over the first metallic layer; a seconddielectric layer over the first primer layer, wherein the seconddielectric layer comprises a first film and a second film; a secondmetallic layer over the second dielectric layer; a second primer layerover the second metallic layer; a third dielectric layer over the secondprimer layer, wherein the third dielectric layer comprises a first filmand a second film; a third metallic layer over the third dielectriclayer; a third primer layer over the third metallic layer; and a fourthdielectric layer over the third primer layer, wherein the fourthdielectric layer comprises a first film and a second film; wherein atleast one of the metallic layers is a subcritical metallic layer.
 2. Thearticle of claim 1, wherein the subcritical metallic layer has aneffective thickness of less than 50 Å.
 3. The article of claim 1,wherein the second dielectric layer further comprises a third filmdeposited over the second film.
 4. The article of claim 1, wherein thethird dielectric layer further comprises a third film deposited over thesecond film.
 5. The article of claim 1, wherein the first dielectriclayer comprises a metal oxide, an oxide of a metal alloy, a nitride, anoxynitride, or a mixture thereof.
 7. The article of claim 6, wherein thefirst film or the second film of the first dielectric layer comprisessilicon nitride, silicon aluminum nitride, or aluminum nitride.
 8. Thearticle of claim 1, wherein the subcritical metallic layer comprisessilver, gold, copper, palladium, or a mixture thereof.
 9. The article ofclaim 1, wherein the first film of the second dielectric layer comprisesa metal oxide.
 10. The article of claim 1, further comprising aprotective coating over the fourth dielectric layer.
 11. A coatedarticle, comprising: a substrate; and a coating over at least a portionof the substrate, the coating comprising: a first dielectric layerformed over at least a portion of the substrate, wherein the firstdielectric layer comprises a first film and a second film; a firstcontinuous metallic layer over the first dielectric layer; a firstprimer layer over the first continuous metallic layer; a seconddielectric layer over the first primer layer comprises a first film anda second film; a second discontinuous metallic layer over the seconddielectric layer; a second primer layer over the second discontinuousmetallic layer; a third dielectric layer over the second primer layer,wherein the third dielectric layer comprises a first film, and a secondfilm; a third continuous metallic layer over the third dielectric layer;a third primer layer over the third continuous metallic layer; a fourthdielectric layer over the third primer layer, wherein the fourthdielectric layer comprises a first film and a second film; and aprotective coating over the fourth dielectric layer.
 12. The article ofclaim 11, wherein the second discontinuous metallic layer has aneffective thickness of less than 50 Å.
 13. The article of claim 11,wherein the second dielectric layer further comprises a third filmdeposited over the second film.
 14. The article of claim 11, wherein thethird dielectric layer further comprises a third film deposited over thesecond film.
 15. The article of claim 11, wherein the first film or thesecond film of the first dielectric layer comprises a metal oxide, anoxide of a metal alloy, a nitride, an oxynitride, or mixtures thereof.16. The article of claim 11, wherein the protective coating comprisestitania, silica, alumina, or a mixture thereof.
 17. A coated article,comprising: a substrate; and a coating over at least a portion of thesubstrate, the coating comprising: a first dielectric layer formed overat least a portion of the substrate, wherein the first dielectric layercomprises a first film and a second film; a first metallic layer overthe first dielectric layer, wherein the first metallic layer comprisessilver, gold, copper, palladium or a mixture thereof; a first primerlayer over the first metallic layer; a second dielectric layer over thefirst primer layer, wherein the second dielectric layer comprises afirst film, a second film, and a third film; a second metallic layerover the second dielectric layer, wherein the second metallic layercomprises silver, gold, copper, palladium or a mixture thereof; a secondprimer layer over the second metallic layer; a third dielectric layerover the second primer layer, wherein the third dielectric layercomprises a first film, a second film, and a third film; a thirdmetallic layer over the third dielectric layer, wherein the thirdmetallic layer comprises silver, gold, copper, palladium or a mixturethereof; a third primer layer over the third metallic layer; and afourth dielectric layer over the third primer layer, wherein the fourthdielectric layer comprises a first film and a second film; wherein atleast one of the metallic layers is a subcritical metallic layer havingan effective thickness of less than 50 Å.
 18. The article of claim 17,wherein the first film or the second film of the first dielectric layercomprises a metal oxide, an oxide of a metal alloy, a nitride, anoxynitride, or mixtures thereof.
 19. The article of claim 17, whereinthe first film of the second dielectric layer comprises a metal oxide.20. The article of claim 17, further comprising a protective coatingover the fourth dielectric layer.